The present invention relates to equipment such as self-propelled cableways travelling on track cables or rails, together with cable installation equipment.
Cableways are frequently used for transporting loads across uneven ground, for example in lumbering and civil engineering. They are based on the principle of the ropeway which requires the use of large winches at one of the ends of the run for pulling the cable. However, such installations have the disadvantage of being heavy, difficult to transport and move and therefore very costly.
Self-propelled equipment travelling on a fixed cable would not require a cable hauling winch located at one of the ends of the run. The installation would be much simpler and easier to dismantle, because it would merely be necessary to stretch a fixed cable between two points. However, the self-propelled equipment travelling along the fixed cable must only have a limited weight.
For installing the conducting cables of a high voltage line a first small cable is installed beforehand between two towers. Once held taut between two supports, the small cable is used for pulling a second cable with a larger cross-section and so on until the final cable pulls the conducting cable. When the ground is negotiable, it is possible to unwind the first small cable from one tower to the next by means of a random heavy vehicle. However, when it becomes difficult to travel along the ground with conventional vehicles, for example when it is a question of crossing valleys, rivers, lakes, mountainous areas, marshes, etc. it is necessary either to use a boat for rivers or a helicopter. However, the use of such vehicles suffers from the disadvantage that they are costly and dangerous. When the helicopter pulls the small cable behind it, the latter could possibly attach itself to a tree or be displaced by a gust of wind, so that the helicopter would lose its balance. The danger is made greater by the fact that the operation must be carried out for each cable.
Various attempts have been made to provide self-propelled means but all have disadvantages, reference being made in an exemplified manner to:
U.S. Pat. No. 3,498,236 (MEEK) discloses a self-propelled device which has only a mediocre adhesion to the cable because the pivot pin of the clamping lever is located in front of the means, leading to poor stability and sliding when transporting loads.